LED luminaires that are recessed in a drop ceiling include a housing that can be fitted into common ceiling grid systems. The housing is commonly an extruded aluminum outer shell that is able to lay on the edge of the ceiling grids. The housing encloses the PSU and the LED module, which is generally attached to a heat sink. The housing also encloses any reflectors that are used in the luminaire as well as a diffuser which generally forms the floor of the housing.
FIG. 1 is an example of a prior art luminaire 10 recessed in a ceiling 12. The luminaire includes an elongated housing 14 having a top wall (not shown), two side walls (only one partially shown), and two end walls (one shown). The bottom of the housing is enclosed by a diffuser 16. Diffuser 16 is held in place by retaining lips 17, 18 which run along length “l” of the lower edge of the housing 14.
A prior art LED luminaire 20 is shown in FIG. 2 in cross-section. The luminaire 20 includes a housing having two regions, top region 22 and bottom region 24. Power supply unit 26 is mounted to the inside surface of the top housing region 22. LED module 28 is mounted to the underside of heat sink 30 which in turn is mounted with two rows of screws 32, 34 so that it is between the top housing region 22 and bottom housing region 24. A diffuser 36 sits in the opening of bottom housing region 24 and reflectors 38 fit within bottom housing region 24 between the LED module 28 and the diffuser 36.
In order to access and replace the PSU 26 of the prior art luminaire 20, the diffuser 36, reflectors 38, and heat sink 30 must first be removed. The diffuser 36 and reflectors 38 are lightweight and relatively simple elements to remove. However the heat sink 30 is heavy and it is awkward to unfasten screws 32, 34 and lower the heat sink from the luminaire. Moreover, heat sink 30 has mounted thereto the LED module 28 which is quite fragile and must be carefully handled to avoid damage. Furthermore, any wiring between the LED module 28 and the PSU 26 must be disconnected in order to remove and replace the PSU 26.
In other words, to remove the heat sink 30 from the prior art luminaire 20, the two rows of screws 32, 34 are removed to release the heat sink 30. The heat sink 30, along with any wiring connecting the heat sink 30, LED module 28, and the PSU 26, is then carefully removed. The PSU 26 is then exposed and can be removed and replaced.
Issues with the prior art assembly are evident. The LED module can be damaged during the removal and temporary storage of the heat sink. The heat sink is heavy and awkward and its removal from the housing can be dangerous.
The above-described shortcomings significantly limit the usefulness of field-serviceable LED luminaires (i.e. luminaires having a replaceable PSU). Therefore, there remains a need for an LED luminaire assembly which allows for the easy and safe removal and replacement of the PSU and other internal components.